Circulatory Stability Research Articles

Impact of high‐dose inotropic donor support on early myocardial necrosis and outcomes in cardiac transplantation

Cardiac donors routinely require vasoactive agents for circulatory stability after brain death. Nevertheless, inotropes have been associated with direct cardiac toxicity. Our study evaluated whether the use of high-dose inotropic support in potential donors was associated with increased early myocardial necrosis (MN) and worse clinical outcomes after cardiac transplantation. The UTAH Cardiac Transplant Program (UCTP) and Intermountain Donor Services databases were queried for records between 1996 and 2009. The high-dose donor inotropic support (HDIS) group was defined as patients on dopamine >10 μg/kg/min. The incidence of early MN, intensive care unit (ICU) length of stay, length of ventilator support, and mortality was evaluated. Two hundred and forty-four recipients undergoing transplant met study criteria. The average donor age was 27 yr. The incidence of MN in the HDIS (n=29) and non-HDIS (n=204) groups was 14.8% and 6.7%, respectively, OR 2.67. Total ischemic time, ventilator support time, ICU stay, and actuarial survival were similar between both groups. The use of high-dose inotropic support to maintain donor stability appears to have a higher trend for early post-transplant MN without an impact on clinical outcomes. With the current growing shortage of organ donors, it appears reasonable to use donors on high-dose inotropic support.

Post Cardiac Arrest Syndrome

Out-of-hospital cardiac arrest (OHCA) is a common initial presentation of cardiovascular disease, affecting up to 325 000 people in the United States each year.1 In a recent meta-analysis of >140 000 patients with OHCA, survival to hospital admission was 23.8%, and survival to hospital discharge was only 7.6%.2 In patients who initially achieve return of spontaneous circulation (ROSC) after OHCA, the significant subsequent morbidity and mortality are due largely to the cerebral and cardiac dysfunction that accompanies prolonged whole-body ischemia. This syndrome, called the post cardiac arrest syndrome, comprises anoxic brain injury, post cardiac arrest myocardial dysfunction, systemic ischemia/reperfusion response, and persistent precipitating pathology3,4 (Table 1). The contribution of each of these components in an individual patient depends on various factors, including prearrest comorbidities, duration of the ischemic insult, and cause of the cardiac arrest. This review focuses on therapeutic strategies and recent developments in managing patients who are initially resuscitated from cardiac arrest. View this table: Table 1. Post Cardiac Arrest Syndrome: Pathophysiology and Potential Treatment Strategies There are 3 major aspects that require consideration in the management of the post cardiac arrest patient. After resuscitation, a decision must be made in relation to the appropriate triage of the OHCA patient. The next phase of management concerns the in-hospital treatment, which must address each component of the postarrest syndrome as appropriate for the individual patient. Finally, there are issues relating to prognostication and the deployment of various secondary prevention measures. Our recommended treatment algorithm is summarized in the Figure. This ideally follows from the implementation of basic and advanced life support measures, including effective cardiopulmonary resuscitation and defibrillation when appropriate, which are major determinants of outcome.2 Such an approach to care may be further modified according to the presence of other comorbidities and precipitating factors, which should be assessed …

Polysialic Acid-Based Micelles for Encapsulation of Hydrophobic Drugs

Despite improvements relative to unmodified counterparts, poly(ethylene glycol) (PEG) conjugation may not be the ideal solution for improving circulatory stability of current nanoparticle carriers or free drugs. Polysialic acid (PSA), a natural polymer for which the body possesses no receptors, has been conjugated directly to biologically active molecules to prevent premature clearance; however, this concept has not yet been applied to nanoparticle drug carrier systems. In the current study, PSA was modified with a long-chain hydrocarbon through reaction of the carboxylic acid side groups with N-decylamine (DA). The resultant PSA-DA conjugates self-assembled into micelles for encapsulation of hydrophobic drug molecules, as demonstrated with Cyclosporine A. Cytotoxicty was dependent on the degree of substitution with DA. On the basis of size and zeta potential, the micelles are capable of passively targeting diseased regions, such as cancer and inflammatory tissue. Further investigations are necessary to explore whether the PSA-based micelles possess stealth properties similar to those of PEG and to establish in vitro and in vivo efficacy.

The clinical efficacy of continuous veno-venous hemofiltration for multiple organ dysfunction syndrome in children

Objective To investigate the efficacy of continuous veno-venous hemofiltration (CVVH)for children with multiple organ dysfunction syndrome (MODS). Methods 30 chilren were divide into treatment group (15 cases) and control group (15 cases) and received antibiotics,vasoactive drugs,nutritional therapy,maintenance of acid-base balance,and mechanical ventilation; the treatmetn group received additional CVVH. Serum levels of cytokines (TNF-α,IL-1,and IL-6) were detected at 0,24,and 48h in the treatment group,and at 0 and 48h in the control group. Mean arteril pressure,ventilator parameters,biochemical indices,blood gas analysis,and PCIS of were determined before and after treatment. 28-day survival rate was compared between the two groups. Results TNF-α and IL-6 were decreased at 24h and 48h and IL-1 was at 48h; the difference was significant (P＜0.05). The indices of circulatory,respiratory,and internal environment stability were obviously improved after treatment (P＜0.05). PCIS score increased (P＜0.05). 28day survival rate was significanfly higer than in the treatment group than in the control group. Conclusions CVVH can effectively remove serum TNF-α,IL-1,and IL-6 in children with MODS,correct disturbance of the internal environment,and improve prognosis. Key words: Continuous veno-venous hemofiltratior; Sepsis; Multiple organ dysfunction syndrome; Children

Demonstration of in vivo stability and lack of immunogenicity of a polyethyleneglycol-conjugated recombinant CHO-derived butyrylcholinesterase bioscavenger using a homologous macaque model

Human serum and recombinant butyrylcholinesterase (rHuBChE) are the most advanced prophylactics against organophosphate (OP) toxicity due to nerve agent or insecticide exposure. For ethical reasons, such potential multi-use treatments cannot be tested in humans and will require extensive testing in animal models and the “Animal Rule” 21 (21 CFR 601.90) for regulatory approval. This will involve multiple injections of rHuBChE into heterologous animals, e.g. macaques, rodents with inevitable immunogenicity and subsequent elimination of the enzyme on repeat injections. In order to accurately assess pharmacokinetics, efficacy and safety of a candidate rBChE in an “antibody free” system, a homologous macaque (Ma) model has been developed. In these studies, macaques received single or multiple intravenous injections of native MaBChE as well as unmodified or PEG-conjugated forms of rMaBChE produced in CHO cells. Compared to the poor plasma retention of unmodified rBChE (MRT: <10 h), three injections of 1.5–2.3 mg/kg of PEG-conjugated tetrameric rBChE resulted in high circulatory stability (MRT: >134 h) and lack of immunogenicity similar to native MaBChE. PEG-conjugation of the monomeric rMaBChE form also exhibited pharmacokinetic profiles comparable to the tetrameric form (MRT: >113 h). However, despite the increased bioavailability of PEG-rBChE, antigenicity studies using sandwich ELISA showed that while macaque BChE was not immunogenic in macaques, PEGylation of rMaBChE did not prevent binding to anti-BChE antibodies, suggesting PEGylation may not be sufficient to mask non-human epitopes on rBChE. This homologous model can provide necessary preclinical protection data for the use of PEG-rHuBChE in humans and bodes well for a safe and efficacious CHO-derived rHuBChE therapeutic.

511: Impact of High Dose Inotropic Donor Support on Early Myocardial Necrosis and Outcome in Cardiac Transplantation

Cardiac donors are routinely placed on vasoactive agents to promote circulatory stability after brain death. Nonetheless these drugs have been associated with cardiactoxic effects. Our aim was to determine whether the use of high doses of inotropes in potential heart donors was associated with increased early myocardial necrosis and longer recovery after heart transplant.

Pre-hospital cooling of patients following cardiac arrest is effective using even low volumes of cold saline

IntroductionPre-hospital induction of therapeutic mild hypothermia (TH) may reduce post-cardiac arrest brain injury in patients resuscitated from out-of-hospital cardiac arrest. Most often, it is induced by a rapid intravenous administration of as much as 30 ml/kg of cold crystalloids. We decided to assess the pre-hospital cooling effectivity of this approach by using a target dose of 15-20 ml/kg of 4°C cold normal saline in the setting of the physician-staffed Emergency Medical Service. The safety and impact on the clinical outcome have also been analyzed.MethodsWe performed a prospective observational study with a retrospective control group. A total of 40 patients were cooled by an intravenous administration of 15-20 ml/kg of 4°C cold normal saline during transport to the hospital (TH group). The pre-hospital decrease of tympanic temperature (TT) was analyzed as the primary endpoint. Patients in the control group did not undergo any pre-hospital cooling.ResultsIn the TH group, administration of 12.6 ± 6.4 ml/kg of 4°C cold normal saline was followed by a pre-hospital decrease of TT of 1.4 ± 0.8°C in 42.8 ± 19.6 min (p < 0.001). The most effective cooling was associated with a transport time duration of 38-60 min and with an infusion of 17 ml/kg of cold saline. In the TH group, a trend toward a reduced need for catecholamines during transport was detected (35.0 vs. 52.5%, p = 0.115). There were no differences in demographic variables, comorbidities, parameters of the cardiopulmonary resuscitation and in other post-resuscitation characteristics. The coupling of pre-hospital cooling with subsequent in-hospital TH predicted a favorable neurological outcome at hospital discharge (OR 4.1, CI95% 1.1-18.2, p = 0.046).ConclusionsPre-hospital induction of TH by the rapid intravenous administration of cold normal saline has been shown to be efficient even with a lower dose of coolant than reported in previous studies. This dose can be associated with a favorable impact on circulatory stability early after the return of spontaneous circulation and, when coupled with in-hospital continuation of cooling, can potentially improve the prognosis of patients.Trial RegistrationClinicalTrials (NCT): NCT00915421

Pharmacokinetics and immunologic consequences of repeated administrations of purified heterologous and homologous butyrylcholinesterase in mice

Aim To assess the consequences of repeated administrations of purified human serum butyrylcholinesterase (Hu BChE) and mouse serum (Mo) BChE into mice. Main methods Purified Hu BChE and Mo BChE isolated from the sera of CD-1 mice were administered into Balb/c or CD-1 mice. The enzymes were delivered by i.m. injections of ∼ 100 U (0.15 mg) on day 1 and on day 28, respectively. The effects of two injections were monitored by following blood BChE and anti-BChE IgG levels. Key findings Hu BChE displayed a mean residence time (MRT) of 50 h, and an area under the curve (AUC) of 1220 U/ml·h in Balb/c or CD-1 mice. Mo BChE exhibited an MRT of 78 h and an AUC of 1815 U/ml·h in Balb/c mice; the AUC increased to 2504 U/ml·h in CD-1 mice. A second injection of Hu BChE in both strains exhibited a marked reduction in circulatory stability. The circulatory stability of the second injection of Mo BChE was reduced in Balb/c mice, but was almost identical to the first injection in CD-1 mice. Consistent with these observations, circulating anti-BChE IgGs were observed in mice injected with Hu BChE; low levels of anti-BChE IgGs were observed only in Balb/c mice injected with Mo BChE. No antibody response was detected in CD-1 mice following either injection of homologous Mo BChE. Significance The identical pharmacokinetic profiles and the absence of an immunologic response following a second administration of homologous BChE support the development of Hu BChE as a detoxifying drug in humans.

Cardiovascular Manifestations of Sedatives and Analgesics in the Critical Care Unit

There are numerous sedatives and analgesics used in critical care medicine today; these medications are used on critically ill patients, many of whom have heart disease, including coronary artery disease or congestive heart failure. The purpose of this review is to recognize the effects of these medications on the heart. Studies that evaluated the effects of sedatives and analgesics on normal individuals or on those with heart disease were reviewed. Current choices for sustained sedation in the critically ill include the benzodiazepines, morphine, propofol, and etomidate. Each of these medications has their particular advantages and disadvantages. Benzodiazepines provide the greatest amnesia and cardiovascular safety but they can cause significant hypotension in the hemodynamically unstable patient. Morphine provides analgesia and cardioprotective activity after ischemia, although the large observational study CRUSADE showed increased mortality rate in those patients with non-ST segment elevation myocardial infarction who received morphine. Propofol is the most easily titratable drug with cardioprotective features, but its use must be accompanied with great attention to possible development of propofol infusion syndrome, which is a deadly disease, especially in patients with head injury and those with septic shock receiving vasopressors. Etomidate has a rapid onset effect and short period of action with great hemodynamic stability even in patients with shock and hypovolemia, but the incidence of adrenal insufficiency during infusion, not bolus doses, may cause deterioration in the circulatory stability. In conclusion, the sedatives and analgesics mentioned here have characteristics that give them a cardiovascular safety profile useful in critically ill patients. However, use of these drugs on an individual basis is dependent on each agent's safety and efficacy.

Stroke Volume Variation as a Predictor of Intravascular Volume Depression and Possible Hypotension During the Early Postoperative Period After Esophagectomy

Perioperative hypotension during esophagectomy results from hypovolemia caused by a shift of extracellular fluid from the intravascular to the extravascular compartment. Fluid management is often difficult to gauge during major surgery because there are no reliable indicators of fluid status, and some patients still experience cardiorespiratory instability. In this retrospective study, we evaluated stroke volume variation (SVV), calculated by using a new arterial pressure-based cardiac output measurement device, as a predictor for fluid responsiveness after esophageal surgery. Eighteen patients undergoing esophagectomy with extended radical lymphadenectomy were monitored by the FloTrac sensor/Vigileo monitor system during the perioperative and immediate postoperative period. Fluid responsiveness was assessed and compared with concurrent SVV and central venous pressure (CVP) values, and routine hemodynamic variables. Eleven of 18 patients needed additional volume loading within the first 10 postoperative hours as a result of hypotension. The maximum SVV value of fluid resuscitated patients was >15% in all cases, whereas six of seven patients without postoperative hypotension had maximum SVV values of <15%. The correlation between SVV and the development of hypotension was statistically significant (P = 0.0012). From the linear correlation analysis of hemodynamic variables influenced by additional fluid loading, SVV was significantly correlated to cardiac output (r = 0.638; P = 0.049), whereas CVP was not (P > 0.05). We conclude that SVV, as displayed on the Vigileo monitor, is an accurate predictor of intravascular hypovolemia and is a useful indicator for assessing the appropriateness and timing of applying fluid for improving circulatory stability during the perioperative period after esophagectomy.

Hypoxia is/is not the optimal means of reducing pulmonary blood flow in the preoperative single ventricle heart

To the Editor : Optimal may depend on the circumstances and both points have utility ([1][1], [3][2]). We found carbon dioxide manipulation more useful and less dangerous than alveolar hypoxia in acute transitional settings when mechanical controlled ventilation is required in unrepaired ductal or

A repeated injection of polyethyleneglycol-conjugated recombinant human butyrylcholinesterase elicits immune response in mice

Human serum butyrylcholinesterase (Hu BChE) serves as an efficacious bioscavenger of highly toxic organophosphorus (OP) compounds. Since there is a concern that the supply of native Hu BChE may be limited, monomeric and tetrameric forms of recombinant Hu BChE (rHu BChE) were evaluated as replacements and found that they lacked sufficient stability in vivo. However, their in vivo stability could be significantly prolonged by conjugation with polyethyleneglycol-20K (PEG) suggesting that monomeric and tetrameric PEG-rHu BChE could function as bioscavengers. Here, the immunogenicity of PEG-rHu BChE was evaluated in mice following two injections given four weeks apart. In addition to pharmacokinetic parameters, such as mean residence time, maximal concentration, time to reach the maximal concentration, elimination half-life and area under the plasma concentration-time curve extrapolated to infinity, the presence of circulating anti-rHu BChE antibodies was also determined. Although the pharmacokinetic parameters were significantly improved for the first injection of monomeric and tetrameric PEG-rHu BChEs, they were much lower for the second injection. Anti-rHu BChE antibodies were detected in the blood of mice following the first and second enzyme injections and their levels were approximately higher by 5-fold and 2-fold in mice injected with monomeric and tetrameric PEG-rHu BChEs as compared to mice injected with unconjugated enzymes. The findings that the rapid clearance of a repeat injection of PEG-rHu BChEs in mice which coincides with the presence of circulating anti-rHu BChE antibodies suggest that PEG conjugation prolonged the circulatory stability of rHu BChE but failed to eliminate its immunogenicity in mice.

The outcome of tactile touch on stress parameters in intensive care: A randomized controlled trial

The study aimed to investigate the effects of a five-day tactile touch intervention in order to find new and unconventional measures to moderate the detrimental influence of patients' stressors during intensive care. The hypothesis was that tactile touch would decrease stress indicators such as anxiety, glucose metabolism, blood pressure, heart rate and requirements of sedative drugs and noradrenalin. A randomized controlled trial was undertaken with 44 patients, which were assigned either to tactile touch or standard treatment (a rest hour). Observations of the stress indicators were made before, during and after the intervention or standard treatment. The study showed that tactile touch led to significantly lower levels of anxiety. The circulatory parameters suggested increased circulatory stability indicated by a reduction in noradrenalin requirement. The results need to be further validated through studies with larger sample sizes.

Effect of polyethylene glycol modification on the circulatory stability and immunogenicity of recombinant human butyrylcholinesterase

The therapeutic value of human serum butyrylcholinesterase (Hu BChE) as a bioscavenger of chemical warfare agents is due to its high reactivity with organophosphorus compounds and prolonged circulatory stability. Native Hu BChE is mostly tetrameric in form while the enzyme produced using molecular cloning technology is a mixture of tetramers, dimers, and monomers. Previous studies revealed that monomers and dimers of recombinant human (rHu) BChE cleared rapidly from the circulation of mice compared to tetrameric rHu BChE and native Hu BChE, which have mean residence times (MRTs) of 18 h and 45 h, respectively. It was also shown that polyethylene glycol-20K (PEG) modification of tetrameric rHu BChE prolonged its circulatory stability and bioavailability in vivo. The goal of this study was to determine if modification with PEG could prolong the circulatory stability and eliminate the immunogenicity of monomeric rHu BChE. Monomeric rHu BChE was expressed in human 293A cells using a cDNA lacking the 45 amino acid tetramerization domain from the carboxyl terminus and the adenovirus expression system. The catalytic and inhibitory properties of purified monomeric rHu BChE were similar to those for native Hu BChE and were not affected by PEG modification. As expected, monomeric rHu BChE rapidly cleared from the circulation of mice (MRT = 3.2 ± 0.3 h) while monomeric PEG-rHu BChE demonstrated significant improvement in its bioavailability and circulatory stability in blood (MRT = 31.4 ± 5.4 h). However, a second injection of monomeric PEG-rHu BChE, 28 days after the first, displayed a much shorter MRT = 11.6 ± 0.4 h, and circulating anti-monomeric PEG-rHu BChE antibodies were detected in the blood of mice. These results suggest that PEG modification increased the circulatory stability of monomeric rHu BChE but failed to reduce or eliminate its immunogenicity.

Early introduction of enteral feeding for patients with percutaneous cardiopulmonary support

Early enteral nutrition has been shown to have a beneficial effect on intestinal integrity and motility, immunocompetence, and patient outcome. Generally, circulatory stability is needed for the introduction but, because there is no precise definition, we might miss the right time to begin. In the present study we attempted to establish early enteral nutrition for patients with cardiogenic shock with a ventricular assist device.

Effect of dopamine and metaraminol on the renal function of patients with septic shock

Vasoactive drugs are often necessary for reversing hypotension in patients with severe infection. The standard for evaluating effects of vasoactive drugs should not only be based on the increase of arterial blood pressure, but also on the blood flow perfusion of internal organs. The effects of dopamine and metaraminol on the renal function of the patients with septic shock were investigated retrospectively in this study. Ninety-eight patients with septic shock were divided into three groups according to the highest infusing rate of metaraminol, with the lightest infusing rate of (0.1 - 0.5, 0.6 - 1.0, > 1.0) microgxkg(-1)xmin(-1) in group A, B and C respectively. Urine output, mean arterial blood pressure (MAP), heart rate (HR), urine output, blood urea nitrogen (BUN), creatinine (CRE), urine albumin (U-ALB), urine beta(2)-microglubulin (Ubeta(2)-MG) and Apache III scores were recorded. Before antishock therapy, hypotension, tachycardia and oliguria occurred to all the 98 patients with septic shock and CRE, BUN, U-ALB, Ubeta(2)-MG and Apache III scoring were abnormal in most cases. With the antishock therapy, MAP, HR, urine output, BUN and CRE in all patients returned gradually to normal (P < 0.05 or < 0.01 compared to those before antishock therapy). U-ALB, Ubeta(2)-MG output and Apache III scoring also reverted but remained abnormal (P < 0.01 compared to those before antishock therapy). No statistically significant differences in the changes of these indices with the time existed among the three groups (P > 0.05). Dopamine and metaraminol when applied to the patients with septic shock could effectively maintain the circulatory stability and promote restoration of renal function.

Human serum butyrylcholinesterase: In vitro and in vivo stability, pharmacokinetics, and safety in mice

The use of exogenously administered cholinesterases (ChEs) as bioscavengers of highly toxic organophosphate (OP) nerve agents is now sufficiently well documented to make them a highly viable prophylactic treatment against this potential threat. Of the ChEs evaluated so far, human serum butyrylcholinesterase (HuBChE) is most suitable for human use. A dose of 200 mg (3 mg/kg) of HuBChE is envisioned as a prophylactic treatment in humans that can protect from an exposure of up to 2 × LD 50 of soman. In addition to its use as a prophylactic for a variety of wartime scenarios, including covert actions, it also has potential use for first responders (civilians) reacting to terrorist nerve gas release. We recently, developed a procedure for the large-scale purification of HuBChE, which yielded approximately 6 g of highly purified enzyme from 120 kg of Cohn fraction IV-4. The enzyme had a specific activity of 700–750 U/mg and migrated as a single band on SDS–PAGE. To provide data for initiating an investigational new drug (IND) application for the use of this enzyme as a bioscavenger in humans, we established its pharmacokinetic properties, examined its safety in mice, and evaluated its shelf life at various temperatures. In mice administered various doses up to 90 mg/kg, enzyme activity reached peak levels in circulation at 10 and 24 h following i.p. and i.m. injections, respectively. The enzyme displayed a mean residence time (MRT) of 40–50 h, regardless of the route of administration or dose of injected enzyme. Mice were euthanized 2 weeks following enzyme administration and tissues were examined grossly or microscopically for possible toxic effects. Results suggest that HuBChE does not exhibit any toxicity in mice as measured by general observation, serum chemistry, hematology, gross or histologic tissue changes. The shelf life of this enzyme stored at 4, 25, 37, and 45 °C was determined in lyophilized form. The enzyme was found to be stable when stored in lyophilized form at −20, 4, 25, or 37 °C to date (2 years), as measured by specific activity and SDS polyacrylamide gel electrophoresis. The effect of storage on circulatory stability was determined by measuring MRT in mice; there was no change in the MRT of lyophilized enzyme stored at −20 °C to date (2 years). These results provide convincing data that HuBChE is a safe bioscavenger that can provide protection against all OP nerve agents. Efforts are now underway to prepare the required documentation for submission of an IND application to the United States Food and Drug Administration (USFDA).

Intraaortic balloon pump counterpulsation after implantation of infrarenal and thoracoabdominal aortic protheses

Highly complex vascular surgery interventions have nowadays become possible due to sophisticated operative techniques and modern intra- and postoperative anesthesiological strategies. Accordingly, the number of high risk vascular surgery interventions rises continuously and thus, the number of secondary complications after high risk interventions increases as well and requires likewise extraordinary treatment concepts. We report of a 68-year old patient who 6 months previously was operated on a ruptured abdominal aneurysm, before he was admitted to our institution for the treatment of a type IIIb (Crawford classification) thoracoabdominal aneurysm. Intraoperatively we implanted a 26 mm Dacron prosthesis which was anastomosed with the previously existing infrarenal graft. Postoperatively the patient suffered from a hemodynamically significant myocardial infarction and acute coronary catheter intervention was necessary. However, circulatory stability could not be reestablished by interventional measures and we therefore decided to implant the intraaortic balloon pump despite the presence of two synthetic aortic grafts. However, the chance of success of such a manoeuver as well as the effectiveness of intraprosthetic counterpulsation was unclear and our literature research undertaken to predict the risk of such a manouver was unsatisfactory. We therefore want to report this case and compile the literature dealing with perceptions and complications of intraaortic counterpulsation after the implantation of synthetic aortic prostheses, since such a treatment option comes to an increased clinical application in comparable constellations.

Polyethylene glycosylation prolongs the circulatory stability of recombinant human butyrylcholinesterase

Previous studies in rodents and non-human primates have demonstrated that pretreatment of animals with cholinesterases could provide significant protection against organophosphate (OP) nerve agent toxicity. Gene delivery/therapy is emerging as an approach to achieve high-level expression of proteins in vivo that are very similar to their native counterparts. Recently, adenoviral (Ad) vectors have proven to be excellent vehicles for delivering genes to cells in vitro and in vivo. In this study, we explored the use of the newly designed AdenoVATOR system for the expression of recombinant human butyrylcholinesterase (rHu BChE) in human embryonic kidney 293A (HEK-293A) cells. In these cells, rHu BChE was expressed as mostly tetrameric form by the simultaneous expression of proline-rich attachment domain. By optimizing the culture conditions, 1.5–2.0 U/ml of rHu BChE could be expressed in HEK-293A cells. Recombinant Hu BChE was purified to homogeneity by ammonium sulfate fractionation followed by affinity column chromatography using procainamide Sepharose and cobalt Sepharose gels. The enzymatic and physico-chemical properties of purified rHu BChE were similar to those of native serum-derived Hu BChE. To determine the suitability of this preparation for use as an antidote against highly toxic nerve agents, its pharmacokinetics were evaluated in mice. Recombinant Hu BChE exhibited a mean residence time of 18.3 h which was 2.5-fold shorter than that observed for native Hu BChE in mice. However, rHu BChE chemically modified with polyethyleneglycol (PEG) displayed a mean residence time of 36.2 h suggesting that PEG-modification can prolong the circulatory stability of rHu BChE. The efficacy of Ad-Hu BChE to induce the production of therapeutic levels of bioscavenger in vivo is under evaluation.

Fluid therapy in sepsis with capillary leakage.

Sepsis is associated with a profound intravascular fluid deficit due to vasodilatation, venous pooling and capillary leakage. Fluid therapy is aimed at restoration of intravascular volume status, haemodynamic stability and organ perfusion. Circulatory stability following fluid resuscitation is usually achieved in the septic patient at the expense of tissue oedema formation that may significantly influence vital organ function. The type of fluid therapy, crystalloid or colloid, in sepsis with capillary leakage remains an area of intensive and controversial discussion. The current understanding of the physiology of increased microvascular permeability in health and sepsis is incomplete. Furthermore, there is a lack of appropriate clinical study end-points for fluid resuscitation. This review considers critically the clinical and experimental data analysing the assessment of capillary leakage in sepsis and investigating the effects of different fluid types on increased microvascular permeability in sepsis.